1. Field of the Invention
This invention relates generally to a cabinet for dispensing rolled sanitary paper products, and more particularly, to a dispensing cabinet in which a roll of sanitary paper is embossed as it is dispensed.
2. Description of the Prior Art
Rolled sanitary paper products such as paper toweling and toilet tissue are commonly dispensed from cabinets in public washrooms. When economy is a primary consideration, a relatively smooth, flat paper is wound very tightly into a roll to maximize the length of paper for a given diameter of the roll. By maximizing the length of paper on the roll, the roll generally lasts longer which increases the time interval between roll replacements. It is also economical to use lower graded papers, such as unbleached or low brightness papers, in these cabinets. Such economy paper can generally be characterized as dense, stiff and having limited absorbency when compared to higher quality sanitary paper products.
When economy is not a primary consideration and it is desired to provide a higher quality rolled sanitary paper product in the dispensing cabinet, the usual approach has been to soften the paper by pre-treating, usually by embossing and perforating, the paper sheet prior to winding it on a roll. As used in this specification, the term embossing means raising the surface of the paper sheet into bosses or protuberances in such a manner that the length of the embossed sheet is substantially the same as the length of the sheet prior to embossing. Depending on the method of embossing, the length of the embossed sheet can be as much as 5% shorter than the length of the sheet prior to embossing, but more typically is in the range of 0-3% shorter than the length of the sheet prior to embossing. One shortcoming of embossing paper prior to winding it on a roll is that the winding operation flattens the bosses formed in the paper with the result that the dispensed paper has less bulk, softness and absorbency than the embossed paper had prior to being wound on the roll. On the other hand, if the pre-treated, embossed paper is wound loosely on the roll in order to retain the bulk and softness from the embossing process, considerably less footage can be wound on the roll and the dispensing cabinet requires much more frequent servicing.
Another shortcoming of dispensing an embossed paper in roll form, particularly in the case of paper toweling, is the fact that in most rolled towel cabinets, the paper toweling is normally dispensed by compressively passing the toweling through a nip formed by two feed rolls. Shelley U.S. Pat. No. 1,224,224 is representative of such a dispensing cabinet. This compressing of the paper tends to reduce the effects of the prior embossing.
One proposal for improving the quality of rolled sanitary products dispensed from a cabinet is disclosed in U.S. Pat. No. 3,935,802 issued to Perrin et al. In that proposal, the paper web in a dispensing cabinet is passed between a drive roll and a driven roll each rotatable about a fixed axis and having formed on the periphery thereof a multiplicity of generally axially extending and circumferentially adjacent teeth. As the plain or smooth paper toweling web is drawn through and variously compressively abutted between the drive roll teeth and the driven roll teeth, and over the various crests of these teeth, it is intended that the web be foldably deformed into a crimped paper toweling web. The treatment of the paper toweling by the rolls is to be controlled so that the paper web does not undergo any appreciable permanent thickness deformation or permanent compression, and so that there is no sacrifice of moisture strength. One disadvantage of that proposal is that the effective length of the dispensed sheet is inversely related to the gain in bulk achieved by crimping. Another disadvantage is based on the well established fact that for sanitary papers, softness and strength are inversely related and, therefore, any bulking process that maintains the moisture strength of the dispensed sheet results in only slight improvement in sheet softness.
Another proposal for improving the quality of rolled sanitary products dispensed from a cabinet involves the concept of embossing the paper as it is dispensed. An apparatus of that nature is described in copending, commonly assigned U.S. Pat. Application Ser. No. 570,824 of Clarence H. Schatz, filed Jan. 16, 1984. The dispensing cabinet described therein includes a pair of embossing rollers rotatably mounted within the cabinet about stationary parallel axes. Each embossing roller is formed of machined steel and includes a plurality of axially spaced circumferential rows of projections extending radially outwardly from a hub. The projections of each row are circumferentially spaced apart to form gaps therebetween, and each row of projections on a respective roller is circumferentially offset relative to an axially adjacent row. Furthermore, the rollers are arranged such that the rows of projections on each roller are axially offset relative to the projections of the other roller. When the rollers are rotated, each of the projections on a respective roller travels closely adjacent a corresponding projection on the other roller and in radially overlapping relationship therewith to stretch and emboss the paper. As a result, the dispensed paper features an enhanced softness and absorbency. While such an embossing mechanism has performed exceptionally well, room for improvement remains. For example, it would be desirable to minimize the effort required to rotate the rollers during an embossing procedure in order to reduce the manual force necessary to manipulate the roller actuating handle of the dispenser. Also, it would be beneficial to improve the visual appearance of the dispensed paper by resisting the formation of wrinkles therein produced during travel of the web through the embossing nip. It would also be desirable to improve the tracking behavior of the paper by enhancing the extent to which the embossing rollers control the direction of travel of the paper through the embossing nip. Further benefits would result if the rollers could be manufactured more economically, e.g., by forming the parts at least partially of plastic, while maintaining acceptable dimensional tolerances of each roller and proper positional relationships between the assembled pair of rollers.
It will be appreciated that the technology of embossing paper webs has been extensively developed in the case of high speed embossing mills in which paper webs are continuously embossed by polished, machined steel rollers rotatable about stationary axes and having embossing projections which mesh at close tolerance to shear the paper fibers as a tensioned web is pulled rapidly through the embossing nip. However, the technological advancements achieved in the case of such mills are not directly transferable to a manually actuable embossing dispenser wherein the force required to rotate the rollers must be minimized to facilitate manual actuation and wherein manufacturing costs must be held down to enable the dispenser to be affordable to the end user. Furthermore, it is difficult to establish and maintain sufficiently precise tolerances within the embossing nip of a wall-mounted, manually actuable paper dispenser to the extent necessary to enable mill-type embossing techniques to be utilized therein.